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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Letters in mathematical physics 23 (1991), S. 287-300 
    ISSN: 1573-0530
    Keywords: 57Q45
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract The elementary string interactions are the Reidemeister moves, birth/death, and fusion/fission. Such interactions have as their trace generically mapped surfaces, and these combine to form knotted surfaces in 4-space. The syzygies among these interactions are moves to such surfaces analogous to the Reidemeister moves for knots. ‘Movie’ parametrizations of these syzygies are given and interpreted in dimension 2+2. A Morse theoretic argument shows there are 15 such movie moves. These moves, with appropriate choices of crossing information, are sufficient to construct any isotopy of an embedded surface on which a height function has been specified. The first seven of the movie moves are parametrized versions of those given by Roseman. The remaining eight are moves of Δ-type. Amplitudes assigned to these interactions must satisfy relations that correspond to the movie moves. One such relation is a Zamolodchikov tetrahedral equation. We present some puzzles about the matrix formulations of these amplitudes.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0887-3585
    Keywords: bioactivity ; SK-hep-1 hepatoma ; interleukin-1 ; recombinant protein ; crystals ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The gene for human interleukin-1β was cloned from SK-hep-1 hepatoma cellular RNA and expressed at high levels in Escherichia coli both as the naturally processed form (rIL-1β) and as a variant with an additional sequence of three amino acids on the N-terminus (rIL-1β+). Expressed protein was purified to homogeneity by a sequence of steps, which included low pH incubation, adsorption and desorption from Procion Red Sepharose, sizing on a Superose 12 fast-performance liquid chromatography (FPLC) column, and anion exchange chromatography on QAE Sepharose. The final step provided a biologically active protein that migrates on twodimensional (2-D) gels as a single spot with a pI of 6.7 ± 0.2 and a molecular mass of 17,500 daltons. Concentrated solutions of rIL-1β have produced crystals by ammonium sulfate precipitation. The crystals are tetragonal, show the symmetry of space group P41 or its enantiomer, have lattice constants of a = 58.46 (1) and c = 77.02 (3) A, and scatter to at least 2 Å resolution. A structure determination based on these crystals is under way.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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